If Your Kids Are Glued to Their iPads, It’s Probably a Good Idea to Unglue Them

Remember when your parents warned that sitting too close to the TV would hurt your eyes? I didn’t really believe it either, but now that I’m a parent to a 6-year-old who yearns to stare at an iPad all day, I can’t help but revisit the issue. Is it possible that our children’s ubiquitous use of tablets, computers, and televisions harms their vision? Is Minecraft giving our kids myopia?

It’s hard to say for sure, but based on what we do know, parents would be wise to take precautions. “We just don’t have a lot of hard evidence,” says Christopher Quinn, president of the American Optometric Association. But eye problems do arise frequently in kids who are glued to screens. “We know from a lot of anecdotal reports that prolonged screen times and exposure to these different kinds of light sources are creating some problems,” he says.

To understand how screens affect our eyes, first consider what our eyes evolved to do. Our ancestors didn’t spend a lot of time reading or looking at screens, so our eyes became best suited to viewing things at a distance. The lenses in our eyes can, of course, change shape to focus in on closer objects—it’s just that our eyes weren’t built to spend lots of time doing it. And images on screens flicker multiple times per second, so they are harder for eyes to focus on than printed materials. Eye doctors therefore worry that when we use screens frequently, we stress our eyes, which temporarily leads to blurred vision, eye strain, and headaches. (Indeed, computer vision syndrome in adults is associated with these exact symptoms.) We also don’t blink as frequently as usual when we look at screens, which can cause dryness and irritation. While you might take periodic work breaks and reach for eye drops when your eyes hurt, kids aren’t likely to stop playing Super Mario Odyssey to do the same.

The bigger concern is that screen use could incite permanent vision problems. Quinn worries it could wear out the ability of kids’ eyes to change focus from near to far and vice versa and that it could also make it harder for kids’ eyes to focus well, although there are no studies showing that screens cause these effects. Screens also emit high-energy blue light; several animal studies suggest that this kind of light can harm the retina at the back of the eye and even contribute to age-related macular degeneration. Even more worryingly, a higher percentage of blue light reaches kids’ retinas than those of adults. But as yet there’s no evidence in kids or adults to suggest that blue light does, in fact, incite serious retinal damage, and some experts say such concerns are overblown.

Some research does, however, suggest that screens could contribute to the onset of problems including near-sightedness and astigmatism. In a studypublished in November, researchers in Italy recruited 320 3-to-10-year-olds and examined their vision in various ways. They also tracked how long the kids spent in front of screens each day. They found that kids who spent more than 30 minutes a day playing video games were more likely than other kids to suffer headaches, eyelid tics, double vision, and dizziness. And 90 percent of the frequent video game players had refractive vision problems such as near- or far-sightedness, particularly in their dominant eyes, compared with only half of the less-frequent gamers. When the researchers looked at overall screen use, they found similar patterns: Kids who used screens for more than three hours a day were much more likely to be far-sighted and have astigmatism than kids who used screens less than that.

This was an observational study in which data was collected at a single point in time—so it’s impossible to establish cause and effect and conclude that screen use caused vision problems in these kids. But other research provides circumstantial support for the idea. A 2015 systematic review and meta-analysis of 27 studies, for instance, found that the more time children spent doing near-work (such as reading, studying, and staring at tablets and TVs), the higher their odds were for developing near-sightedness. (Across the globe, the incidence of near-sightedness has been increasing, but no one knows if this increase is related to increased screen use or not.) There’s also evidence that kids who spend more time outdoors are less likely to be near-sighted than other kids. These studies don’t prove that screens are dangerous, but it’s easy to see why eye doctors are concerned.

I know, I know: It’s hard to limit kids’ screen time. And many classrooms incorporate screens, which parents can’t do much about. But to limit the potential negative effects, teach your kids to follow the 20-20-20 rule: After every 20 minutes using a screen, look at something 20 feet away for 20 seconds. Quinn also says to be sure that your kids’ eyes are examined yearly by an optometrist or ophthalmologist to address any burgeoning issues. Yes, yearly—pediatrician and school-based screenings are not enough to catch all problems. (My son is a case in point: He has an eye problem that our pediatrician never noticed.) And as much as I hate to admit it, our parents were probably right: We shouldn’t let our kids sit too close to the screen.

Melinda Wenner Moyer is a science writer based in Cold Spring, New York, and is Slate’s parenting advice columnist.